The 99 genes differentially expressed by 40% CR, but not 40% CR + IGF-1, were significantly represented in the maturity onset of diabetes pathway (three genes, P = 0.016), the PPAR signaling pathway (four genes, P = 0.017), and 50 genes related to macronutrient metabolic processes (P < 0.001) (Fig. 3B). Here, IGF1 is linked to diabetes mellitus.